Blockade of amygdala metabotropic glutamate receptor subtype 1 impairs fear extinction.

Full Abstract

The metabotropic glutamate receptor subtype 1 (mGluR1) is thought to be crucial for several forms of memory, but its role in memory extinction has not been determined. Here, we examined a role of mGluR1 in the extinction of conditioned fear using microinjection of an mGluR1 antagonist, CPCCOEt, into the lateral amygdala (LA), a critical structure for fear conditioning and extinction. Intra-LA injection of 3 microg CPCCOEt impaired extinction that was initiated 48 h after the conditioning, but not that initiated 2h after the conditioning, indicating that the effectiveness of CPCCOEt depends upon the length of time since fear conditioning. The CPCCOEt injection failed to alter an mGluR1-like receptor (mGluR5)-dependent acquisition of fear memory, further supporting the specificity of the injected CPCCOEt on mGluR1. Together, our results suggest that amygdala mGluR1 plays a critical role in the extinction of learned fear, but not in the acquisition of fear memory.

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Author information

Author/s: Kim, Jeongyeon (J); Lee, Sukwon (S); Park, Heewoo (H); Song, Beomjong (B); Hong, Ingie (I); Geum, Dongho (D); Shin, Kisoon (K); Choi, Sukwoo (S);

Affiliation: School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 151-742, Republic of Korea.

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't

Journal: Biochemical and biophysical research communications (Biochem Biophys Res Commun), published in United States. (Language: eng)

Reference: 2007-Mar; vol 355 (issue 1) : pp 188-93

Dates: Created 2007/02/23; Completed 2007/04/10;

PMID: 17292864, status: MEDLINE (last retrieval date: 12/26/2008)

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Amygdala - physiology
Animals
Chromones - pharmacology
Conditioning (Psychology) - drug effects; physiology
Electroshock
Extinction, Psychological - drug effects; physiology

Fear - physiology
Male
Memory - drug effects; physiology
Rats
Rats, Sprague-Dawley
Receptors, Metabotropic Glutamate - antagonists & inhibitors

Associated Chemicals: 7-(hydroxyimino)cyclopropan(b)chromen-1a-carbxoylic acid ethyl ester (0) ; Chromones (0) ; Receptors, Metabotropic Glutamate (0) ; metabotropic glutamate receptor type 1 (0)

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